5.4.4 Configurations using resource servers

This subsection explains a configuration in which shared resources are shared among multiple servers by using resource servers.

Organization of this subsection

(1) Number of resource servers
(2) Concept of a resource server configuration

(1) Number of resource servers

You can specify only one resource server for a group. The maximum number of resource servers that can be placed on a single host depends on the maximum number of servers that are run on a single host, which is specified in the servmax operand in the HA Monitor environment settings.

The following shows the maximum number of resource servers that can be placed for each maximum number of servers that is specified in the servmax operand.

When the maximum number of servers is 16: 8
When the maximum number of servers is 64: 32
When the maximum number of servers is 128 or greater: 64

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(2) Concept of a resource server configuration

Resources include shared disks, file systems, and LANs. You can share one resource among multiple servers and dedicate the other resources to individual servers, or you can share multiple resources via a single resource server.

(a) Possible configurations

You can use a resource server to achieve the following configurations:

Use the resource server to share multiple shared resources
Use the resource server to share one of the shared resources and allocate the remaining shared resources to individual servers

The figure below shows a configuration in which multiple shared resources are shared by using a single resource server. In this example, servers A and B share the shared disk and alias IP address.

Figure 5‒4: Configuration in which multiple shared resources are shared by using a single resource server

The figure below shows a configuration in which one of the shared resources is shared by using a resource server and the remaining shared resources are allocated to individual servers. In this example, servers A and B share the shared disk and use separate alias IP addresses.

Figure 5‒5: Configuration in which one of the shared resources is shared by using a resource server and the remaining shared resources are allocated to individual servers

(b) Impossible configuration

A single shared resource cannot be shared among multiple servers or resource servers. All servers that share a shared resource must belong to the same group as the resource server.

For example, in the configuration shown below, a single shared disk is used by a resource server and by server C, which does not belong to the server group. This configuration cannot use the resource server to share the shared resource.

Figure 5‒6: Configuration that cannot use a resource server to share a shared resource

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